import java.util.Set;
import java.util.stream.Collectors;

public class StudentCountVisitor implements PaperSelectionVisitor {
    private int count;

    @Override
    public void visit(PaperSelection selection) {
        Set<Student> students = selection.getSelections().values().stream().collect(Collectors.toSet());
        count = students.size();
    }

    public int getCount() {
        return count;
    }
}    